Sunan Ibn Majah, Book 1, Hadith 315 (In-Book) ⓘ
It was narrated that Anas bin Malik said: "Whenever the Messenger of Allah entered the toilet, he would say: 'A'udhu Billahi minal-khubthi wa'l-khaba'ith (I seek refuge with Allah from male and female devils).'"
حَدَّثَنَا عَمْرُو بْنُ رَافِعٍ، حَدَّثَنَا إِسْمَاعِيلُ ابْنُ عُلَيَّةَ، عَنْ عَبْدِ الْعَزِيزِ بْنِ صُهَيْبٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ إِذَا دَخَلَ الْخَلاَءَ قَالَ " أَعُوذُ بِاللَّهِ مِنَ الْخُبُثِ وَالْخَبَائِثِ " .
also referenced under: Hadith 298 (Reference) & Volume 1, Book 1, Hadith 298 (DarusSalam)